1. Field of the Invention
This invention relates generally to image and/or information display systems and, in one non-limiting embodiment, to an improved display system utilizing light emitting, e.g. fluorescent material(s), which is particularly useful in a vehicle head-up, display system.
2. Technical Considerations
An information display system displays an image, e.g. but not limited to black and white, and/or colored stationary objects, moving objects, alphanumerical characters, to convey information to a viewer. One such information display system is a head-up display (HUD) system. The heads-up display system displays information, such as an image, to a viewer while the viewer simultaneously views the real world around and through the displayed image. Head-up display systems are often incorporated into aircraft cockpits and/or transparencies for pilots to monitor flight information. More recently, head-up display systems have been used in land vehicles, such as cars, trucks, and the like. The displayed image is generally positioned so that the vehicle operator can see the image from a normal operating position and does not have to glance downwardly to the vehicle dashboard and away from the viewing area in front of the vehicle.
A conventional head-up display system typically includes a matrix of light emitting diodes (LED), which can be selectively illuminated to form an image. A collimator aligns the light rays from the LEDs and directs them toward a combiner that reflects the image toward the viewer. For automotive use, laminated windshields have been used as the combiner. Examples of automotive head-up display systems are disclosed, for example, in U.S. Pat. Nos. 2,264,044 and 5,013,134, and International Publication No. WO 91/06031, all of which are herein incorporated by reference.
While these known vehicle head-up display systems are generally adequate for automotive use, improvements could be made. For example, in these conventional automotive head-up display systems the resolution of the reflected image is limited by the size of the LED matrix, i.e., the number of rows and columns of LEDs used to generate the image. Additionally, in strong sunlight, the reflected image from the LED matrix can be difficult to read. Further, reflection of the image from each of the interfaces of the windshield, especially the air-glass interfaces, creates multiple images that can reduce overall image clarity. Moreover, these conventional head-up display systems are designed so that only the vehicle operator, not vehicle passengers, can view the reflected image. Additionally, if the curvature of the windshield deviates from designed specifications, the reflected image can appear distorted and can be difficult to discern.
Therefore, it would be advantageous to provide an information display system, particularly an automotive head-up display system, which reduces or eliminates at least some of the drawbacks discussed above.